Semiconductor Device, Electrical Device, and Method of Controlling Power Source

1. A semiconductor device, comprising: an atmospheric pressure value obtaining unit configured to obtain an atmospheric pressure value from an atmospheric pressure sensor; a moving state determining unit configured to determine a moving state of the semiconductor device as one of a moving state in an automobile, a moving state on a train, a walking state, and a running state; and a control unit configured to detect a variance state of the atmospheric pressure value obtained with the atmospheric pressure value obtaining unit, wherein said control unit is configured to control an on state and an off state of a power source of a GPS (Global Positioning System) device according to a determination whether the variance state satisfies a specific condition, said control unit is configured to control the on state and the off state of the power source of the GPS according to the specific condition corresponding to the moving state determined with the moving state determining unit, said moving state determining unit includes a geomagnetic sensor configured to determine the moving state of the semiconductor device as the moving state in the automobile or the moving state on the train, and wherein said control unit is configured to determine whether the semiconductor device is located in a tunnel according to the variance state and the specific condition, and said control unit is configured to control the power source of the GPS to turn off when the control unit determines that the semiconductor device is located in the tunnel, wherein said control unit is configured to control the power source of the GPS to turn on when the control unit determines that the semiconductor device is not located in the tunnel, said GPS device is configured to detect a position thereof based on a GPS signal received therewith and output positional information.

2. The semiconductor device according to claim 1 , further comprising a map information obtaining unit configured to obtain map information, wherein said control unit is configured to specify the tunnel according to the map information obtained with the map information obtaining unit and the positional information output from the GPS device just before, the power source of the GPS is turned off when the control unit determines that the semiconductor device is located in the tunnel.

3. The semiconductor device according to claim 2 , wherein said control unit is configured to detect an exit of the tunnel according to the map information, and said control unit is configured to control the power source of the GPS to turn on and input a position of the exit into the GPS device when the control unit determines that the semiconductor device comes out from the exit and is not located in the tunnel.

4. The semiconductor device according to claim 1 , wherein said control unit is configured to determine the specific condition according to a correlation between the moving state and the specific condition, said correlation being determined in advance.

5. The semiconductor device according to claim 1 , wherein said atmospheric pressure value obtaining unit is configured to determine an obtaining period of time during which the atmospheric pressure value obtaining unit obtains the atmospheric pressure value according to a. correlation between the moving state and the obtaining period of time, said correlation being determined in advance.

6. An electrical device comprising: said semiconductor device according to claim 1 : said GPS device configured to detect the position thereof based on the GPS signal received therewith; a power supplying unit configured. to supply power to the GPS device; and a display unit configured to display a position detection result of the GPS device.

7. A method of controlling a power source of an electrical device having a GPS (Global Positioning system), comprising: an atmospheric pressure value obtaining step of obtaining an atmospheric pressure value from an atmospheric pressure sensor; a detection step of detecting a variance state of the atmospheric pressure value obtained in the atmospheric pressure value obtaining step; a moving state determining step of determining a moving state of the electrical device as one of a moving state in an automobile, a moving state on a train, a walking state, and a running state with a moving state determining unit including a geomagnetic sensor; and a power source controlling step of controlling an on state and an off state of a power source of the GPS device according to a determination whether the variance state and/or the moving state satisfies a specific condition, wherein said control unit is configured to determine whether the semiconductor device is located in a tunnel according to the variance state and the specific condition, and said control unit is configured to control the power source of the GPS to turn off when the control unit determines that the semiconductor device is located in the tunnel, wherein said control unit is configured to control the power source of the GPS to turn on when the control unit determines that the semiconductor device is not located in the tunnel, wherein said GPS device is configured to detect a position thereof based on a GPS signal received therewith.